vd_lavc: ridiculous workaround for Libav 9 compatibility

This "sometimes" crashed when seeking. The fault apparently lies in
libavcodec: the decoder returns an unreferenced frame! This is
completely insane, but somehow I'm apparently still expected to
work this around. As a reaction, I will drop Libav 9 support in the
next commit. (While this commit will go into release/0.3.)

1 files changed, 10 insertions, 0 deletions

diff --git a/video/decode/lavc_dr1.c b/video/decode/lavc_dr1.c
index 03e2b5b873..f730a6c231 100644
--- a/video/decode/lavc_dr1.c
+++ b/video/decode/lavc_dr1.c
@@ -204,6 +204,16 @@ void mp_buffer_ref(struct FrameBuffer *buf)
     pool_unlock();
 }
 
+bool mp_buffer_check(struct FrameBuffer *buf)
+{
+    pool_lock();
+    bool ok = buf->refcount > 0;
+    if (ok)
+        buf->refcount++;
+    pool_unlock();
+    return ok;
+}
+
 void mp_buffer_unref(struct FrameBuffer *buf)
 {
     FramePool *pool = buf->pool;